Jeffrey D. Sachs, Professor of Sustainable Development, Professor of Health Policy and Management, and Director of the Earth Institute at Columbia University, is also Special Adviser to the United Nations Secretary-General on the Millennium Development Goals. His books include The End of Poverty, Co…read more

Our Summer of Climate Truth

NEW YORK – For years, climate scientists have been warning the world that the heavy use of fossil fuels (coal, oil, and natural gas) threatens the world with human-induced climate change. The rising atmospheric concentration of carbon dioxide, a byproduct of burning fossil fuels, would warm the planet and change rainfall and storm patterns and raise sea levels. Now those changes are hitting in every direction, even as powerful corporate lobbies and media propagandists like Rupert Murdoch try to deny the truth.

In recent weeks, the United States has entered its worst drought in modern times. The Midwest and the Plains states, the country’s breadbasket, are baking under a massive heat wave, with more than half of the country under a drought emergency and little relief in sight.

Halfway around the world, Beijing has been hit by the worst rains on record, with floods killing many people. Japan is similarly facing record-breaking torrential rains. Two of Africa's impoverished drylands – the Horn of Africa in the East and the Sahel in the West – have experienced devastating droughts and famines in the past two years: the rains never came, causing many thousands to perish, while millions face life-threatening hunger.

Scientists have given a name to our era, the Anthropocene, a term built on ancient Greek roots to mean “the Human-dominated epoch” – a new period of earth’s history in which humanity has become the cause of global-scale environmental change. Humanity affects not only the earth’s climate, but also ocean chemistry, the land and marine habitats of millions of species, the quality of air and water, and the cycles of water, nitrogen, phosphorus, and other essential components that underpin life on the planet.

For many years, the risk of climate change was widely regarded as something far in the future, a risk perhaps facing our children or their children. That threat would, of course, have been reason enough to act. Yet now we understand better that climate change is also about us, today’s generation.

We have already entered a new and very dangerous era. If you are a young person, climate change and other human-caused environmental hazards will be major factors in your life.

Scientists emphasize the difference between climate and weather. The climate is the overall pattern of temperature and rainfall in a given place. The weather is the temperature and rainfall in that place at a particular time. As the old quip puts it: “Climate is what you expect; weather is what you get.”

When the temperature is especially high, or rains are especially heavy or light, scientists try to assess whether the unusual conditions are the result of long-term climate change or simply reflect expected variability. So, is the current US heat wave (making this the hottest year on record), the intense Beijing flooding, or the severe Sahel drought a case of random bad weather, or merely the result of long-term, human-induced climate change?

For a long time, scientists could not answer such a question precisely. They were unsure whether a particular weather disaster could be attributed to human causes, rather than to natural variation. They could not even be sure that they could detect whether a particular event (such as a heavy rainfall or a drought) was so extreme as to lie outside the normal range.

In recent years, however, a new climate science of “detection and attribution” has made huge advances, both conceptually and empirically. Detection means determining whether an extreme event is part of usual weather fluctuations or a symptom of deeper, long-term change. Attribution means the ability to assign the likely causes of an event to human activity or other factors. The new science of detection and attribution is sharpening our knowledge – and also giving us even more cause for concern.

Several studies in the past year have shown that scientists can indeed detect long-term climate change in the rising frequency of extreme events – such as heat waves, heavy rains, severe droughts, and strong storms. By using cutting-edge climate models, scientists are not only detecting long-term climate change, but also are attributing at least some of the extreme events to human causes.

The past couple of years have brought a shocking number of extreme events all over the planet. In many cases, short-run natural factors rather than human activity played a role. During 2011, for example, La Niña conditions prevailed in the Pacific Ocean. This means that especially warm water was concentrated near Southeast Asia while colder water was concentrated near Peru. This temporary condition caused many short-term changes in rainfall and temperature patterns, leading, for example, to heavy floods in Thailand.

Yet, even after carefully controlling for such natural year-to-year shifts, scientists are also finding that several recent disasters likely reflect human-caused climate change as well. For example, human-caused warming of the Indian Ocean probably played a role in the 2011 severe drought in the Horn of Africa, which triggered famine, conflict, and hunger, affecting millions of impoverished people. The current US mega-drought probably reflects a mix of natural causes, including La Niña, and a massive heat wave intensified by human-caused climate change.

The evidence is solid and accumulating rapidly. Humanity is putting itself at increasing peril through human-induced climate change. As a global community, we will need to move rapidly and resolutely in the coming quarter-century from an economy based on fossil-fuels to one based on new, cutting-edge, low-carbon energy technologies.

The global public is ready to hear that message and to act upon it. Yet politicians everywhere are timid, especially because oil and coal companies are so politically powerful. Human well-being, even survival, will depend on scientific evidence and technological know-how triumphing over shortsighted greed, political timidity, and the continuing stream of anti-scientific corporate propaganda.

Comments

OK. But the discussion is not really about whether humans are changing their environment, but about whether or not to do something about it, and if so, what, and then, who gets to pay. It is not clear that the cost of the changes is greater than the cost of alternatives, or less. Also the folks likely to bear most of the cost are not necessarily the same as the ones who would get to pay for an alternative. Finally some things even widespread deaths might or might not be preferred to other things for example a World State-like control over economic activity....

I suggest, and I am far from alone on this, that those of us who DO believe that humans are causing climate change with large costs to be imposed upon us as a result, REALLY OUGHT to focus on those alternatives that are most likely to combine the most relief at the most acceptable cost and with the least resistance. Read more

The evidence for climate change has been around for a long time. In a stable dynamic environment, all time records are broken with a predictably diminishing frequency, since each sets a higher bar for the next.

This has demonstrably not been true for the past century, disproving the hypothesis of climate stability.

There seems to be a childish assumption that if it is not our fault, we can't be expected to deal with it. Even now staring into the barrel of the gun, we seek confirmation that we are to blame before taking evasive action.

Were you around in the 1960s when we saw Earth from the Moon? Do you remember Club of Rome and "Limits to growth", Schumacher and "Small is Beautiful" in the 1970s? Do you remember the "Mankind has always found a way" argument being misused to argue against the existence of any limits ever? Our childeren's children are no longer the future - they are now nearly as old as we were then.Individually, mankind can demonstrate logic and common sense of the highest order, yet as a species we seem to be no smarter than lemmings. Except in science fiction we accept the damaging dichotomy between our intelligent selves and the distorted cultural messages we accept from those in power.Will our new communication capability, with its spectum of potential that stretches from Project Syndicate to Twitter, help our human intelligence to break free from the complacency of recent generations, or are they still too powerful? Read more

good to see gary marshall can take time from his exhaustive posting of economic remedies to comment on agw. Gary if you were to read up on the subject you would know that scientists have good explanations and models that explain the dust bowl and other events. The present events cannot be explained without greenhouse gases added to the mix. Please spread your disinformation elsewhere.

P.S. i'm still waiting for my check for debunking that ridiculous idea of eliminating taxes and replacing them with borrowing Read more

Gary, the Moon also achieves extremely low temperatures not paralleled on Earth. The lack of any atmosphere or water causes very high variability in the temperature of the Moon, and, of course, since the Moon has a rotation period of approximately 27 days, the hottest points on the Moon will get much hotter than the Earth. Your water vapor argument is both non-sequitur and factually incorrect. Even if human activity did not affect water vapor levels, since carbon dioxide is still a greenhouse gas, the increase in temperature due to increased carbon dioxide would still induce climate change. But moreover, human activity DOES affect water vapor levels, namely because water vapor levels increase with temperature (higher temperatures make more water evaporate), and thus the emission of other greenhouse gases is magnified by the increase in water vapor. Read more

No. From the last you had mentioned government setting up some sort of fund. I told you I had no idea why government would borrow money and put into this fund. And then you repeated the scenario without explaining it.

If the fund were a pension plan, where government funded its expenditures by borrowing and issuing paper to be repaid under some pension scheme, then I understand what you are speaking of. Otherwise, I didn't get your point. So if you wish to continue discussing it here, please feel free.

I see, so the models that have failed to predict a period in which there has been no significant global warming must be believed!

The GCMs, which predict based upon a flat earth construction, give suitable approximations of the earth's climate past and present?

The greatest greenhouse gas is not carbon dioxide, which amounts to less than 380 ppm. It is water vapour. And we have little control over water vapour in the atmosphere.

If the earth is to turn to tinder, then why does the moon with no such atmosphere attain greater daily temperatures than the earth laden with such an atmosphere? It seems the earth to warm to such a lunar degree should shed its greenhouse laden atmosphere in favour of none, don't you agree?

It can no longer be attributed to coincidence. There is mounting evidence that human activity is driving this. The "coincidence" argument is a bad attempt to misinterpret climate change through weather. (Climate is a long term expectation, weather is a random realization of the climate variable)

Increasingly more studies are coming out which support the theory of MMCC. For example:

"Prof Michael Mann, director of the Earth Science System Center at Penn State University, said that there was "a certain ironic satisfaction" in seeing a study funded by the Koch Brothers "demonstrate what scientists have known with some degree of confidence for nearly two decades..."

http://www.bbc.co.uk/news/science-environment-19047501

Now, even if there is uncertainty, can we afford inaction given the risks? Id say no! Read more

Sachs seems to be writing from hearsay rather than from things he actually knows. The current US drought is not the worst in the 20th century, the 1930s and 1950s droughts were worse.

While he's right overall about climate science, his final words fall with a myopic thud.

"Yet politicians everywhere are timid, especially because oil and coal companies are so politically powerful." Tell that to the South Korean politicians who recently voted for their carbon price legislation with 146 votes in favour and 3 abstemtions. That is hardly timid!

Tell it to the Saudis who are investing $109billion in solar power over the next 20 years. Not a timid investment.

His writing would carry more weight if his rhetorical flourishes were aimed with more accuracy - at the US Congress and Senate. Read more

How could an intellectual of the caliber of Dr. Sacks make the mistake of attributing coincidence to causation. When it comes to climate science many individuals have suspended the superb powers of reasoning they posses. Read more

As we can see from the comments these arguments for human made climate change are never going to convince people however logical and factual they look, as people can always bring about earlier natural phenomenon erasing what today's scientists are saying so we do not have to examine even the possibility whether with our life and attitude we could contribute to such changes.I guess even such fact sheets we saw on BBC a couple of months ago about humanity running out basically of all the presently used important energy resources and crucial natural elements used in most up to date products within 30 years would not convince them as they could show other publications promising other resources even if they require highly unnatural, or potentially harmful methods to harvest.But what might convince even the most die hard fans of our present lifestyle is that today even those institutions, mechanisms we ourselves built are slipping through our fingers, and although we had 100% certified methods governing, guiding them, today with each step we try to make harnessing our finances, economics, politics, education or the basic human foundations like family just cause even deeper crisis, deeper breaks and there is no end or solution in sight.Our constant quantitative growth, expansive and exploitative system, that does not take into consideration anything else but self calculation, self profit has run into a dead end, because it is unsustainable in our closed, finite system, especially today when humanity itself has evolved into a single, interconnected and interdependent network.Unless we pull our heads out of the sand and start taking the scientific facts, transparent information around us seriously, and we do not try to squash them because they would logically force us to change ourselves, we will blindly fall off the cliff where we drove ourselves to with our previous and present attitude and lifestyle.It does not matter in this respect that it comes in the form of natural disasters, or economic collapse, or civil wars or external wars as our human system collapses. Read more

He has nothing to do in this discussion. Commenting against every single person he disagrees with in this discussion, using aggressive comments does not speak well of him. When someone has something worthwhile to say, its usually not spread everywhere like butter.

What caused the far more severe drought in the 30's? Was that AGW too? How about the Medieval Warming Period? How about Greenland when it was actually green and the Viking settlers were buried in the soil.

A UN advisor advocates for the slimy UN and its causes. What a big surprise!

Robert Skidelsky
on why the right economic policies cannot work without the right public expectations.

Project Syndicate provides readers with original, engaging, and thought-provoking commentaries by global leaders and thinkers. By offering incisive perspectives from those who are shaping the world's economics, politics, science, and culture, Project Syndicate has created an unrivaled global venue for informed public debate.